Means for automatically cutting off the feed-motion of machine-tools



N. J. OLSSON. MEANS FOR AUTOMATICALLY CUTTING OFF THE FEED MOTION OF MACHINE TOOLS. APPLICATION FILED JUNE 22, I918. 1,349,222. Patented Aug. 10,1920.

2 SHEETS-SHEET I.

Y N. J. OLSSON. v MEANS FOR AUTOMATICALLY CUTTING OFF THE FEED MOTION OF MACHINE TOOLS.

APPLICATION FILED JUNE 22 I918.

Patented Aug. '10, 1920.

2 SHEETSSHEET 2.

FIQ.5

@ mm @wvk 8 M UNITED STATES NILS JOSEF OLSSON, 0F GOTTENBORG, SWEDENJASSIGNOR T0 PATENT- OFFICE.

AKTIEIBOLAGET SVENSKA' KULLAG-ERFABRIKEN, 0F GOTTENBORG, SWEDEN, A CORPbiRA- TION' OF SWEDEN.

Application filed June. .22,

To all whom it may concern Be it known that I, Nrns Josnr OLssoN, a subject of the King of Sweden, residin at Gottenborg, in the Kingdom ofi Swe en, have invented -certain new and useful Irnproved Means for Automatically Cutting Off the Feed-Motion of Machine-Tools, of which the following is a specification.

This invention relates-to automatically operating devices. for cutting ofi the feed motion of grinding machines or other machine tools when the work reaches its desired diameter, and particularly to devices of that class in which a pivotally mounted lever bears constantly upon the work or upon a member bearing, in turn, upon the work. In heretofore known devices of the said kind, a contact in a circuit controlling the stopping of the feed motion is successively moved, as the diameter of the work is reduced, to a position in which it closes the circuit. Such devices, however, have not proved absolutely reliable, as a closing of said circuit may already occur before the desired diameter has been exactly reached owing to the formationof a spark bridge between the contacts during the final steps of the grinding operation during which the distance between said contacts is very small.

According to this invention, the said'inconvenience is overcome by so arranging-the pivotally mounted lever bearing against the work or against a member, bearing in turn upon the work, and so forming the said lever at the contact point that, when the desired diameter of the work has been reached, the lever will by means of a' spring, a weight w or the like he brought out of engagement with the work, thus initiating the cutting Ofi" 0f the feed motion. I l

I In the accompanying drawings some ein- .bodiments of the invention are illustrated.

Figui'e 1 is a cross-section of a: device constructed in accordance with one embodiment of the invention Fig. 2 is an elevation of said device shown from the right of Fig. 1.- F-i s. 3 and 4 show modifications of thelever. ig. 5 isaside elevation and Fig. 6 is a horizontal section-of a device constructed according to another 'embodi-. ment of the invention. I f

- Referring to Figs. 1 and 2, 1 indicates a Specification of Letters Patent. I Patent d A 10 1920 1918. Serial no. 241,392. I

casing inclosing a lever 33, 4 mounted on the pivot 2, one arm 3 of said lever extending through an opening 5 of the casing, the other arm 4 being formed as a hammer.

'Mounted below said hammer is a contact spring 6 adapted-to cooperate with an underlylng fixed contact piece 7. The arm 4 is controlled by. a spring 8 tending to keep the lever 3, 4 in the position, in which the hammer keeps the spring 6 in contact with the fixed contact 7. The hammer of the arm 4 is formedwith a hook-shaped portion 9 adapted to cooperate with a pawl 10 for keeping the lever out of operative position.

The contacts 6 and 7 are intended to be Included 1n the circuit of an apparatus for cutting off the feed motion of the grinding machine or other machine tool in'connection with which the device'is intended to be used. Said apparatus may be of any convenient or known type and will not be described as it does not form any part of this invention. The distance between the contacts 6 and 7 should be so chosen that the tension existing in the said circuit will.

with grinding machines for external grinding operations.

H When the. apparatus is to be used, the lever 3, 4,;is locked by means of the pawl 10, intheposition shown by dotted lines in Fig. -1, whereupon the casing 1 is so adjusted by means of the screw 12 that the arm .3 of thejleter 3,4 will upon the release of the lever be brought in contact with the 'circumference 'of the work beneath the horizontal diameterithereof and can be moved upward past"said central position only after the-{work has reached the desired diameter.

The-work 13' should be rotated in the direc tion of the arrow so as not to tend to press .theflarm 3 upward past the said central no tendency for premature circuit closing,

inasmuch as the lever 3, 4 is completel out of'engagement with the contact sprin 6 before .it has passed the central position. The normally existing distance between the contacts 6 and 7, which is lar e enough to prevent'the formation of spar s, will thus be constant until the moment, at which the closin is to take place.

In t yembodiment above referred to, the

end of the arm 3 is rounded after an arc ,with small radius so that the uttermost point of said arm will bear against'the work only at the moment, at which the lever arm 3 passes the central position, The wear in the point determining the cutting off action will, thus, be exceedingly small. The form of the arm 3 may, however, be so modified- -as to prevent, in a still higher degree, changes of the efl'ective length of the arm owing to the wear caused by the work. {Two 40 ting ofi:' operation exactly, at the desired '-'to a machine for ofa ball bearin ring.

such embodiments are shown in Fig. 3 and 4 respectively.

Referring to 'Fig. 3, the end of the arm 3 is formed as an arc the center of curvature of which'coincides with the center of the pivot of the arm 3, 4. With this construction the effect of the wear on the reliability of the apparatus is practically completely eliminated the lever .3, 4 initiating the cutmoment as long as any point of theoriginal are remains unaltered 6. during. a practically unlimited time, inasmuch as the are proper is in contact with the workat releasing moment only.

In the embodiment shown in Fig. 4, a preferably hardened steel ball 14 is mounted in the end of the arm 3, said ball being kept in place in any suitable-manner and may after wearing be adjusted so as to turn an unaffected point toward the work thereby 'restorin the original. length-.of the lever arm. nstead of the steel ballI may use another object of any suitable hard material, as for'instance a diamond.

In Figs. 5 -and 6 a ,releasing'devi'ce is shown" which may be j'used 'in combination with grinding inachine's'for internal as well as for externalgri'nding' operations. In the drawing the invention is shown as applied In this embodiment, the arm 3 of the lever 3,]4bears upon one arm 15 of a lever 15,

the

grinding the inner surface 16 pivotally mounted to move in a plane at right angles to the plane in which the lever 3, 4 moves. The arm 16 of the lever 15, 16

carries a rotatably mounted roller 17101: the

like adapted. to bear upon the surface to be ound, as shown in Fig. 6. The arm 15 is ormed with anoblique surface 18 adapted to be enga ed by )the end of the arm 3 the lever 3,4 t us tending, under the action of its spring,,to keep the lever 15,16 with the roller 17 in such position that the said roller constantly bears upon the surface to be 7 ground. The apparatus should be so ad- Lusted that, when the surface to be ground as reached its desired size, the arm 3 can leave the arm 15 and out off the feed motion in any well known orsuitable manner.

scope or principle of the invention be so modified as to initiate the said cuttingofi' action by opening an electric circuit.

' The apparatus may be further modified by causing the lever 3, 4 to operate a completely mechanical device for initiating the cutting off of the feed motion. p

. A further modification is disclosed in my co-pending application, Serial No. 247,784, filed Au st 1, 1918.

What claim is:

' 1. In a device for automatically cutting off the feed motion of machine,tools, ,the combination ofga pivoted'trip member one end of whichengages the unfinished work and thereby holds it in inoperative position, and means controlled thereby to operate a feed motion cut ofi, the member being re-,

leased from engagement with the work substantially at the instant when the work has reached a predetermined size and thereby actuaitfing the operating means of the feed out o Y 2.. In a device for automatically cutting off, the feed motion of machine tools,'the

combination of a pivoted trip member, one

1 end of which engages. the unfinished. work below a line drawn from the' pivot point of the member to the center, of the .work, and

means controlled thereby'to operate za feed I motion cut ofi, the member being normally held out ofoperative'engagement with the operating meansof the, feed cut off and being trippedsubstantially-at the instant when the work has reached. a predetermined size, and therebyactuating theope'rating means of the feed cut ofi.

g 3. In a device for automatically cutting of Contact elements controlling a feed mo-- off the feed motion of machine tools, the tion out off and the said pivoted member becombination of a pivoted: trip member, 'o'ne ing released from engagement with the work 10 end of which engagesthe unfinished work, substantially at the instant when the work 5 and the other 'of which is weighted, and a has reached a predetermined size.

'pairof contact elements, adapted to be op- In testimony whereof I afiix my si nature. erated by said weighted end, the said pair NILS J OSEF OL SON. 

